different thing; another thing; exception
Used to emphasize that something is fundamentally different from what was mentioned or expected, not just a variation. Often implies a qualitative gap.
彼の考え方は私とは別物だ。
His way of thinking is completely different from mine.
This drama is a completely different thing from the original.
This dish is on a whole different level of deliciousness compared to yesterday's.
Talent and effort are two different things.
You should think of work and romance as separate matters.
例外 means 'exception' and focuses on something breaking a rule or pattern, while 別物 focuses on a thing being categorically different rather than rule-breaking.
別個 means 'separate, individual' and is used for treating things as distinct items without implying a quality gap, whereas 別物 emphasizes that something is fundamentally, qualitatively different.
同類 means 'the same kind/category', the direct opposite of 別物's sense of belonging to a fundamentally different category.
別途 is an adverb meaning 'separately/additionally' (about procedure), while 別物 is a noun meaning 'a different thing' (about category), so learners often confuse them because both start with 別.
Compound of 別 (different) and 物 (thing). The meaning is transparent from its components.